ahci.ko in RELENG_8_2, what about atacontrol cap?

[Patrick M. Hausen]

Hello,

Am 02.04.2011 um 11:40 schrieb Jeremy Chadwick:
> You want "camcontrol identify adaX".  DO NOT confuse this with
> "camcontrol inquiry adaX" (this won't work).
> 
> identify = for ATA
> inquiry  = for SCSI

Works perfectly, but I just noticed one really odd thing:

1. boot without ahci.ko:

nas-pmh# atacontrol cap ad4
...
write cache                    yes	yes


2. boot with ahci.ko:

nas-pmh# camcontrol identify ada0
...
write cache                    yes	no


Well? ;-) The system is a HP NL36 - I just found a couple
of articles mentioning that the default setting in the BIOS
setup was write cache disabled. I can check that in the
next couple of days when I take the machine back to the
lab (no monitor/keyboard at my home office).

I'd prefer a way to make sure write cache is enabled via
some tuning from FreeBSD. The disks are dedicated to
a raidz2, so from what I found around the net, write cache
should not pose a major problem. Of course, one will lose
_some_ data at a power outage - what I want to avoid
for home office use is a completely lost file system.
Losing the last time machine backup of my Mac is tolerable.

Thanks,
Patrick
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